Exemplary embodiments described herein relate to a substrate treating apparatus and methods of substrate treating, and more particularly, to an apparatus for exposing a substrate and methods of exposing the substrate.
Generally, semiconductor devices are manufactured by repeating a process of sequentially depositing thin films so as to form a predetermined circuit pattern. A plurality of unit processes, such as a deposition process, a photolithography process and an etching process, are performed so as to form and deposit a thin film.
A photolithography process is a process for forming a pattern on a wafer. The photolithography process includes a photoresist coating process, an exposing process and a developing process. The top layer on a wafer is etched using a pattern formed on a wafer by a developing process, so that a device according to a pattern can be formed.
A photoresist coating process is a process of uniformly depositing a photoresist coating which is sensitive to light on a surface of a wafer using a coater. An exposing process is a process of transferring a circuit pattern onto a wafer that includes a photoresist layer by passing a light through a circuit pattern formed on a mask using a stepper. A developing process is a process of developing a portion of the photoresist through which light passes during the exposing process using a developer.
When the processes described above are performed by individually separated apparatuses, a wafer process line is relatively long. As a result, the wafer can be easily contaminated, due to the extended period of time taken to transfer the wafer from one apparatus to another apparatus, during which time the wafer is exposed to the atmosphere. To solve the problem, an in-line type substrate treating apparatus in which a coater, a developer, a baking unit and a stepper are sequentially disposed with an established arrangement has been developed.
An in-line type substrate treating apparatus performing a photolithography process includes a spinner apparatus performing a coating process and a developing process, and a scanner apparatus performing an exposing process which transfers a pattern to a wafer when the coating process is completed. A wafer is transferred between the spinner apparatus and the scanner apparatus by an interface unit disposed between the spinner apparatus and the scanner apparatus.
A wafer stage on which a wafer is placed is provided in the scanner apparatus. When a particle having a size of greater than 0.5 μm is present on a wafer stage, a focus depth of a lens at a position where the particle is present is out of a standard value, which induces a defocus phenomenon. As a result, a resolution of a photoresist layer is degraded due to the defocus phenomenon to cause an abnormal process.